Motor-control system



Jan. 1, 1924 L. J. HIBBARD MOTOR CONTROL SYSTEM Filed Jan. 5. 1921 2 Sheets-Shea?l 1 INVENTOR Lloyd J Hmmm wlTNEssEs: l 15./ J

ps2 g ATTORNEY Jan. 1, 1924 1,479,179

L, J. HIBBARD v MOTOR CONTROL SYSTEM lNVENTOR www mf/wmf ATTORNEY Patented Jan. 1, 1924.

UNITED STATES PATENTVOFFICE.

LLOYD J. HIBBARD, OF WILKINSBURG, PENNSYLVANIA, ASSIG-NOR T WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

MOTOR-CONTROL SYSTEM.

Application filed January 5, 1921.

To ZZ whom it 'may concern.'

Be it known that I, LLOYD J. HmisAiin, a citizen of the United States, and a resident of lVilltinsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Motor-Control Systems. of which the following is a specification.

My invention relates to motor-control sysl tems and it has particular relation to control systems for operating electric locomotives.

The Aobject of my invention is to provide a. motor-coiitrol system for governing an electric locomotive, whereby the number of contactors will be greatly reduced although securing effective and desirable starting and accelerating characteristics for the locomotive.

In order to obtain desirable starting characteristics, the initial steps must be so graduated as to take out the slack in the train smoothly. In oider to obtain desirable ac celeratiiig characteristics. the accelerating steps must be so graduated as to give smooth notching and maintain the average value of accelerating tractive effort as near to the slipping-point. of the wheels as is practicable.

It is desirable to maintain the accelerating tractive effort as near this point as possi ble, thereby more quickly bringing the loco motive to full speed and lessening the time in which resistors are required in circuit with the secondary windings of the locomotive. This action becomes necessary, since the energy consumed by the resistors is lost and, `furthermore. if the resistors are suhjected to a heavy current for a considerable period of time. they tend to become heated to a dangerously high value.

Heretofoi'e. the propelling motors of an electric locomotive have been operated simultaneously during the starting and accelerating periods. but. inV my invention, the motors are either operated singly, successively, or in pairs, successively, thereby reducing the number of contactors requiredL to startaiild accelerate the locomotive and train for any predetermined number of starting and accelerating steps.

Serial No. 435,102.

For a better understanding of my inven tion, reference should be made to the accompanying drawings- Figure 1 of which is a diagrammatic view, in side elevation, of an electric locomotive; Fig. 2 is a diagrammatic view of a master controller employed to govern the operation of the locomotive shown in Fig. 1;

Fig'. 3 is a schematic view of a plurality of motors which operate the locomotive shown in Fig. 1, and which are governed by the master controller shown in Fig. 2.

Fig. 4 is a chart, of well-known form, showing the sequence of operation of the contactors and circuit-breakers that are employed to operate the motors shown in Fig. 3; and

Fig. 5 is a curve chart indicating the manner in which the motors are accelerated.

.Referring to Fig. 1, :i locomotive 1 is. mounted upon driving trucks Q. and 3 and bogie trucks 4 and The driving wheels 6 of each main truck are. mechanically connected in groups by suitable rods 7. A plurality of propelling motors 8 and 9 `are mcchanically connected to the driving wheels 6 of the front truck Q by suitable gearwheels 11 and driving rods 12, and motors 13 and 14 are similarly connected to the driving wheels 6 of the rear truck Referring to Fig. each of the motors. 8. 9, 13 and 14 is provided with a primaryphase winding 15 and a secondary-phase winding 16. The primary windings 15 of the motors 8, 9, 13 and 14 may be energized from a source of electrical energy (not shown) through suitable supply conductors 17, when a. plurality of three-phasc circuitbreakers 1S. 19, 2t) and .31 are closed` resiiiectively. v

A, plurality of sets ot resistors 2? are re spectively connected in circuit with the secu ondary windings 16 of the motors S. 9, 13 and 14. A plurality of contactors "23 lo 11S, inclusive, are employed to accelerate the inotors S, 9, 13 and 14, by shuntiug portions of the starting resistors 22. lt is to be understood that more contactors may be employed to shunt different' portions of the starting resistors 22, if it is considered necessary. For the sake of simplicity, aminimum num ber of contactors are shown; but they are sufficient in number to fully illustrate my invention.

ln Fig. :2, a master controller 39 is provided with a contact segment a of suitable contour for engaging a plurality of conta -t fingers l-l in the desired sequence. The master controller 39 is provided with a starting position and with a plurality of operating positions, a to g?, inclusive.

The operation of the motor 8 is begun by actuating the master controller 39 through the starting position to position a, thereby establishing a circuit from a suitable source of energy, such, for example, as a batter f e2, through contact fingers al and contact segment el() Vof the master controller 39 and the actuating coil of 'the circuitbrealrer 18. The motor 8 will tend to operate at its lowest speed since the corresponding resistors 22 are entirely in circuit with its secondary lphase winding lo.

The master controller 39 is next actuated to its second, l), third, c and fourth, d, positions successively, thereby energizing theV actuating coils of the three-phase circuitbrealrers 19, and 2l, causing them` to close.

The wheels of the locomotive l will begin to rotate as soon as the motor 8 is energized, and the locomotive will start pulling a few cars that are nearest it, in a forward direction. lllhen the engineer believes that the increasing load is such that the locomotive is about to stop, he actuates the master controller forward another notch. lle must repeat this action each time that it be-` comes apparent that the power of the motor is not sutiicient to draw the next few stationary cars in a forward direction.

If the engineer should accelerate the locomotive too rapidly, there is danger that the draw-bars of some of the cars will be impaired; therefore, the desirable tractive effort per notch for a locomotive is necessarily limited by the character of the rolling stock it is to haul and by the number of cars in the train.

After all the slack has been removed from the train, corresponding` to the occupation of position Z, for example, of the master controller, the locomotive and cars may be accelerated to full speed. Generally, the tractive effort per truck that can be maintained without exceeding` the slipping-point of the wheels is the limitingfactor by the time all of the slack has been taken up. Hence, it becomes desirable to distribute the load per notch uponthe driving wheels of both the Vforward and the rear trucks.

After the yslack has been removed from the train, or the tractive effort per truck approximates the slipping-point of the wheels, the acceleration of the motors 8, 9, i3 and le is accomplishedby actuating the mast'? ret/9,179

controller through positions m to p, inclusive. `When the master controller 39 is actuated from position. Z to position m, accelerating contactors 3l and 35 are closed, in accordance with the sequence chart shown in Fig. 4, thereby shunting portions of the corresponding resistors 22 which are in circuit with the secondary windings 16 of each of the motors 8 and 13.

`When the master controller 39 is actuated from position m to position n, contactors '32 andBG close, thereby shunting the remaining portions of the resistors 2:2 which are in circuit with the secondary windings 16 of the motors 8 and 18, thus bringing the phase windings of theindividual motors in balanced relation to each other.

The motors 9 and 14; are next-.accelerated by the master controller 39 being actuated to position o, thereby closing contactors 33 and 3? and thus shunting portions of the resisters 22 which are in circuit with the motors 9 and 14, respectively. lVhen the master controller 39 is actuated to position p, contactors 34 and 38 are closed to again accelerate the motors 9 and la, respectively, and balance their secondary phases.

Approximately the same tractive effort of the locomotive per notch of the master controller may be secured during. the aceleration of the train by closing the contactors 33 and 3.7 simultaneously, after closing contactors 3l and 35 and before closing contactors 32 andV 36. However, this method of accelerating the motors would cause the load upon the phase windings to be unbalanced for a considerable longer period than by the method first set forth.

The graphs or curves shown in 5 show the approximate relation of the speed to the tractive effort of the motors of the locomotive per notch. tiu'ves i3 show the relation of the speed to the tractive elfort during the period the locomotive is taking the slaclr from the train positions a to Z, inclusive). Curves ehi show the relation of the speed to the tractive ed'ort during the afneleration of the locomotive thereafter.

lf the allowable variation per notch between the minimum desirable tractive effort, represented by the line d5, and the maximum allowable tract-ive effort, represented by the line i6, is equal to a variation in the tractivc effort of the locomotive per notch, a more desirable and effective acceleration may be obtained bvmaintaining the acceleration between smaller limits, as repre sented by a line f7 and the line 46. This condition gives variation in tractive effort per notch, since the average accelerating tractive effort has been increased from line 4-7 to a line half 'vvav between lines 47 and 46, and the notching will he smoother.

it is evident that, by having all of- `the tract-ive eti-ort `increment per notch or posi- CII llld

tion of the master controller produced by one motor during all or part of the starting period and by a pair ot' motors during the accelerating period, the necessary number of contactors is reduced as compared with prior systems. To effect the same total increase in tractive etlioit by operating all motors simultaneously each notch, tour times as many contactors would be required and only one-fourth the effective variation in resistance in circuit with the secondary winding of each motor could be obtained per notch.

It would also be within the spirit of my invention to accelerate the motors upon one truck successively before accelerating the motors oit another truck. However, more satisfactory operation may be secured by alternately accelerating each set of driving wheels.

While I have shown my invention in a preferred form, it is apparent that minor modifications may be made in the arrange ment of apparatus and control circuits without departing from the spirit of the invention. I desire, therefore, to be limited only by the scope of the appended claims.

I claim as my invention:

l. In a motor-control system, the Acombination with an electric locomotive having a plurality ot' driving wheels and a plurality of motors for actuating said driving wheels, each of said motors having a plurality of windings, oi means for alternately accelerating said motors through a plurality ot steps while maintaining the relation of said .vindings. l

2. In a motor-control system, the combination with an electric locomotive having a plurality of driving Wheels and a plurality of motors for i ctuating said driving wheels, each oit said motors having a plurality ott windings, of means for successively increasing the torque ot said motors throughout a number of steps while maintaining the relation oit said windings, said increase in torque of each motor being substantially equal to the allowable accelerating rate of said locomotive.

3. In a motor-control system, the combination with an electric locomotive having a plurality ol driving wheels and a. plurality of motors for actuating said driving wheels, each of said motors having a plurality of windings having a predetermined number of poles, otmeans for successively increasing the torque of said motors while maintaining the number ot said poles constant, said increase in torque ot' each motor corresponding to the maximum variation in torque per notch during the starting period of said locomotive.

4. In a motor-control system, the combination with an electric locomotive having a plurality ot sets of driving wheels, means for mechanically connecting the wheels of the sets together and a plurality of motors provided with primary and secondary windings for actuating said sets of wheels, of a master controller having a plurality of positions for governing said motors, said controller being capable of accelerating said motors successively through a number of positions while maintaining the relation of said windings.

5. In a motor-control system, the combination with an electric locomotive having a plurality of trucks provided with driving wheels, means for mechanically connecting the driving wheels of each truck, and a plurality of groups of motors for actuating said wheels, eac-h of said motors having a plurality of windings, of a master controller having a plurality of positions for so governing said motors that the groups of wheels of said ytruck are accelerated successively step by step while maintaining the relation of one winding to another.

6. In a motor control system, the combination with a locomotive having a plurality of wheels arranged in groups, a plurality of motors for actuating said wheels, each of said motors having a plurality ot co-operating windings and a plurality of translating devices in circuit with one of said windings, ot means for varying the connections of said translatingl device successively, whereby a motor which actuates one group of wheels is repeatedly accelerated prior to the repeated acceleration of a motor actuating another group ot wheels.

7. In a motor-control. system, the combination with a. plurality ot' wheels arranged in groups, a plurality ot motors tor actuating said wheels, each of said motors having a primary and a secondary winding, and a resistor in circuit with each of said secondary windings, of means for shunting said resistors successively to secure step-by-step acceleration of said motors, whereby a plurality of motors which actuate different groups of wheels are alternately accelerated.

8. In a motor-control system, the combination with a plurality of wheels, means for mechanically connecting said wheels, and a plurality ot-motors for actuating said means, each of said motors having a prede termined number of poles, of means for alternately accelerating said motors while maintaining constant the number of poles of said motors.

9. In a motor-control system, the com-A bination with a plurality of wheels, means for mechanically connecting said wheels, and a plurality of motors for actuating said wheels, each of said motors having a primary and a secondary winding, of a plurality of resistors in circuit with said secondary windings of said motors, a plurality ot contactors for shunting said resistors, and a master controller for so governing said contactors that said motors are accelerated alternately.

10. ln a motor-control system, the combination with a plurality ot motors, ot means tor accelerating said motors successively during a portion ot the starting period and afterwards accelerating certain of said motors in pairs.

11. ln a motor-control system, the combination with a plurality ot motors, of means for first accelerating said motors successively in accordance with predetermined conditions and second accelerating groups ol said motors successively.

12. The combination with a locomotive having a plurality oit Wheels said Wheels eing mechanically connecteoL in groups, ot a plurality ot motors tor actuating said wheels, and means for lirst accelerating said motors successively during a portion of the starting period and aftterivarcL accelerating said motors in groups.

18. The combination with an electric locomotive having a plurality of Wheels mechanically connected in groups, ot means comprising a plurality oi"- motors and a plu rali y of current-varying devices for `accelerating said groups of Wheels alternately' by operating said devices.

lll. The comb'nation with an electric loco motive having a plurality ot Wheels mcchanically connected in groups, ot means for alternately accelerating said groups ot Wheels and later accelerating said groups ot Wheels simultaneously.

15. The combination with an electric locomotive having plurality of Wheels, a plurality ot motors tor driving Vsaid Wheels, means for mechanic-ally connecting certain of said motors to said Wheels, and means for navarro iirst accelerating said motors alternately and after-Ward accelera-ting certain of said motors simultaneously.

1G. The combination with a locomotive having a plurality ot driving wheels mounted upon trucks, a plurality ot' motors ar-Y ranged in pairs tor actuating said driving Wheels, means for mechanically connecting the driving Wheels o' each truck to the corresponding pair ot' motors, and means tor accelerating said motors alternately and simultaneously.

1?. rlfhe method of starting and accelerating a locomotive having a plurality of driving motors that comprises actuating said motors alternately and later Vaccelerating groups ot said motors simultaneously.

18. The method of start-ing and accelerating a locomotive having a plurality oi? driving Wheels driven by said motors that comprises accelerating said motors successively until the maximum allowable tractive effort per Wheel is secured and then accelerating said motors in groups to distribute approximately the same tractive eftort upon a greater number of Wheels.

19. The method of starting and accelerating a locomotive having a plurality of driving Wheels mechanically connected in groups and a. plurality of motors for actuating said groups that comprises accelerating said motors successively until the maximum allowable tractive eli-ort per notch tor a group of Wheels has been secured and then accelerating said motors, in groups, thereby distributing the maximum allowable tractive effort per notch over a greater number of Wheels. y

In testimony whereof, I have hereunto subscribed my name this 19th day of December, 1920.

LLGYD J. HBBARD. 

